I recently tried several dewatering techniques, Heat-and-let-settle, Spray hot oil through the air, electric frypan. None did what I wanted. All these require that the oil go round-and-round til it may finaly be dry ( high humidity in illinois never did let it get really dry). you have to keep testing the oil and run the process for however long it takes, I wanted to run the oil through a process once and be assured it was dry. -- FOUND IT .. FLASH EVAPORATION ...With this method you pump cold, wet oil into the heater and get absolutly dry, hot oil out.

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EDIT - 09-04-06 -- It has been pointed out that I need to add some background here to help clarify info on basic mechanical design of the unit and also the basic concept of the flash evaporator.

This dry oil can then be collected into a separate container and immediately used, no waiting for the entire batch to get dry and no testing needed. It does take a bit of electricity, I figure around 2 cents per gallon on my prototype but I was not recovering any of the heat with it, the new unit will pre-heat the incoming wet oil by running it through tubing emersed in the outgoing hot condensed steam (around 200 deg F) and hot (300 degree f) oil. Everything will get wrapped in insulation. I think this will recover at least 1/2 the heat so the additional heat should only cost about 1 cent/gallon.

In the "sugar in WVO" thread (here,2nd and 5th posts down) Magnito describes his large flash evaporator, it does around 5 gallon a minute, my small unit does about 2 gallon/hour. His evaporater is a modified pressure type oil fired steam genny. This is way bigger than I need ( only need a couple gallons per hour if it can run unattended 24 hours/day) and his big unit has to be monitored continuously. I came up with a small version using an 1100 watt electric water heater element for the heat and a 12 volt shurflo RV pump to pressurise the oil to 90-150 pounds to keep the water from boiling inside the heater pipe, flow rate is about 2 1/2 gallon/hour.

The pressurized wet oil is heated by the water heater element inside a 12 inch long piece of 1 inch pipe, the heater is screwed into a "T" on one end of the pipe, the oil is input into the side of this same "T", the 300 degree hot,wet oil comes out the other end of the pipe through some sort of small oriface, the water immediately flashes off into steam due to the reduction in pressure. I initially used a ball valve as an orifice and sprayed the oil/steam into a cooking pot. This works (I dewatered 25 gallon this way, absolutely NO bubbles seen, not one, using the "frypan bubble test") but there is a fair amount of oil vapor that drifts off with the steam, it condenses on everything in sight , it also is a big fire hazard. I am now working on the next generation that uses a fixed size orifice from a oil fired furnace burner unit and sprays the hot oil/steam into a couple of small tanks (2 quart),the first tank seperates the steam from the oil, then the steam-with-oil-vapor goes into a second tank where the steam is condensed into water and the oil vapor is condensed back to liquid oil, the oil floats on the water so they can easily be seperated using a gooseneck grease-trap type method.

The flow through this unit is a balance between heat, pressure and flow rate. You want to keep the oil temp at around 300 deg f so if you add more heat you need to increase the flow rare linearly, twice the heat = twice the gallons/hour etc, as long as the pump can hold the pressure you can build the unit to dry what ever gallon/hour you want.

I am using a shurflo rv pump for the pressure. I was amazed that these pumps will create way over 150 pounds pressure (and survive, at least so far). I adjusted the pressure cutoff switch to 150 pounds and the pump cycles off at 150 pounds and back on at 90 pounds. I am working on a pulse width modulated electronic motor control for the shurflo pump that will hold a more constant pressure. You could also use a fueloil pump from an oil fired furnace burner, it does this exact same job on the oil burner.

On the prototype I ran the heater continuously and controlled the oil temp by slightly opening/closing the ball valve. This works but you have to tweek it every few seconds. On the new unit I am using a constant flow burner orifice and will use a thermostat to control the heater, this way the unit will run without needing to be watched or tweeked.

I think this unit can be reduced to fit in the space of less than one cubic foot. It also could be built to run entirely on 12 volt DC power for mobile dewatering

Here is a picture of the prototype dewatering oil. The steam can sorta be seen as lighter patches floating away from the pot, hard to see in a still pic.

This message has been edited. Last edited by: Tim c cook, September 05, 2006 12:09 AM

Originally posted by Tim c cook:... I think this unit can be reduced to fit in the space of less than one cubic foot. It also could be built to run entirely on 12 volt DC power for mobile dewatering.

This sounds very much like the idea I had for heating WVO using Exhaust heat.

Original idea- Wrap exhaust (or make a donut) that fits around exhaust. Use 12v pump to push oil thru the thing at a rate that accomidates the raise in temprature desired. Pump controled by a thermastat. Too hot of oil and shut off pump. Heated oil goes to smaller "drive" fuel tank (not directly to IP) Drive tank has overflow that pushes oil back to storage tank.. If drive tank temp drops too much then process starts over. PROBLEM. You need a variable rate pump to accomidate fluxuation in exhaust heat. (cooler right after start up / hotter at operating temp etc.) Can you vary pump rate by lowering voltage going to it? Will this ruin a pump though?

Now thats the drive tank idea. Apply this to your flash idea would make the drive tank a cooling/storage tank cause 300 degrees to hot for fuel use.

Wonder if you could use one of the inline vapor bleed type fuel filters for getting the water vapor out. These vapor bleed filters were desinged for autos than needed a solution for vapor lock issues. The vapor was sent back to the fuel tank. What is different in this idea though is it would not use a mist action via a jet to help the vapor seperate out.

For example the super heated oil moves back toward storage tank going thru an inline vapor bleed fuel filter. Oil moves on, vapor goes to a condensor tank where vapor condenses and mixes with the little amount of oil that went with it.

just clarifying about your flashing. (keep your raincoats on you pervert LOL Talking about Fuel Flashing.

So your saying you super heat the oil (above boil point of water and below flashpoint of oil) and then this super heated oil gets "misted" via some sort of nozzle back into a container. The mist contains also water vapor (steam). The vapor travels upward and bye bye. The oil travels downard into the container. Your prototype lets vapor escape into space. Your production model intends to catch this vapor in a second container.

Right so far?

My question is how do you ensure the water vapor does not condense on the walls of the first container or other plumbing that the vapor is suppose to travel and end up back in the first container remixing with the oil.

A method Ive used recently for removing a lot of suspended fats in WVO, is to add 10% vol/vol BioDiesel glycerine to the oil, before the glyc had been de-methylated.

The water has a greater affinity for glycerine/methanol/NaOH mixture than veggy, The fats clump together and settle out, rather like the first stage of cheese-making! The particulate matter containing water is also settled out to a great extent, except for the odd bits that happen to float, but these are fairly large and are easily sorted.

The whole lot settles out at amazing speed, and the oil is crystal clear in a day or two, The fats are a LOT whiter at this stage, having been 'scrubbed' of the darker veggy oils. The time it takes for the oil on top to become crystal clear depends on the ambient temperature, when in open settling tanks

I use this as a pre-treatment in my BioDiesel making process, to increase the vol of useable veggy over fats ( We only supply 100% BioDiesel, so a low gell point is essential, Normally I achieve a BioDiesel CFPP of -8 to -10 by this pre-treatment method.)

Todd T -- Dewaters in one pass. This was what I was looking for, the oil is ready to use as it comes out of the unit, no waiting for the entire barrel to dry. It is DRY oil, don't need to do any testing to find out.

1 inch pipe fittings -- If you measure a 1 inch pipe coupling or "T" the opening will measure about 1 1/4 inch. Pipe diameter is based on the INSIDE diameter of the PIPE so the outside diamrter will be larger. Look over the fitting, it will be marked with the pipe size cast into it someplace, these cast-in numbers can be hard to read sometime, usualy you can see what looks like a "l" someplace.

The heater elements for normal home water heaters have the same diamiter and number of threads/inch as 1 inch pipe but the threads are STRAIGHT rather than TAPERED as pipe threads are. They match the smallest diamiter of normal pipe threads so fit a bit loose into a pipe fitting. I sometimes grind off as much as 1/4 inch of the end of the fitting so the remaining internal threads are becoming smaller in diamiter and more closely fit the heater. Also using a lot of teflon tape helps, or better yet is to use teflon paste, use your finger to insure that paste gets between all the threads, both on the outside threads of the heater and on the inside threads of the coupling. I had some leakage from the rubber gasket that came with the heater, just a drop now and then, I dought it is specked for 300 degrees, I have not yet tried just leaving this gasket off, depends how well the threads get sealed.

jmj -- Exhaust heat -- been thinking a bit about this, more complicated due to the veriable flow rate as you indicate. Thinking thus far is to use a shurflo type pump controled by a pressure sensor. The shurflo can deliver 150 pounds up to a flow rate of at least 10 gallon/hour so by controlling the motor speed from off to full on and all places in-between the constant pressure of 150 pounds can be had at all usable flow rates. I was thinking of using a needle valve as the orifice. the needle valve could easily be opened/closed by a servo motor by whatever amount is nescicary to keep the oil at 300 deg f temp. If the oil is at 300 deg and under 150 pounds pressure the water should flash off no matter the actual size of the outlet oriface. A bit of electronics controling a cheap stepping motor could easily screw the needle valve open/closed to keep the oil temp around 300 deg f(temp not realy critical, 250-300 probably will work ok, need to test this to be sure).

I suspect this unit would be located inside the front fender or at least inside the engine bay. The flash tank I am working on now is only 5 inches in diamiter and a foot tall so this same tank could do the oil/steam seperation. Even with the nternal heat exchange tubing preheating the incomming oil the oil in this flash tank should stay well over 212 degrees. I think, and the tank will be insulated so I don't think there is any problem condensing steam in this tank. I saw NO condensation inside or outside the pot during the cooking pot tests.

Your discription of a mist of oil/steam is not quite how I would describe it, You get mostly liquid hot oil(check the pic), any mist is steam that also contains just a slight bit of vaporized oil. the oil/water coming from the oriface has 150 pounds pressure behind it and when the water comes out of the orifice it flashes to steam only thousents of an inch outside the orifice, and at 300 degrees, It expands many, many times in volume and tends to RISE, sometimes vilantly away from the oil. I think it will rush out of a 1/2 inch hole in the top of the flash tank just fine. It then will go into a second small tank partialy filled with water, the steam tube outlet will be well below the water line, the steam should condense quickly as will the small amount of oil vapor. the oil will end up floating on the water, 2 seperate outlets from the tank will run the water one way and the oil back to the supply tank to insure it gets dewatered eventualy (this may not be a problem ?)

The oil in the bottom of the flash tank need not be (and should not be , I think) returned to the wet oil supply tank, it is absolutly DRY (for our requierments anyway), ready to use oil, run it off to a seperate supply tank. This is what I realy like about this setup, dry oil in seconds-- no waiting for days, no test-and-dry-more -- it is ready to use..

---------------------------------------------------------------------92 dodge cummins with over 260,000 miles. Running an unheated 50% diesel/50% WVO blend for about the last 75,000 miles when temps above 50 deg f, no modifications or heating except the addition of a throw-away in-line fuel filter (removed during cold weather). As of 8-01-05 I have been testing a 75% WVO/15% gasahol (90% RUG/10% ethanol)/10% diesel blend. Works fine down to about 65 f then starts rough. Runs ok once engine warms up. Back to a 50/50 diesel blend sence 9-15-05, just to cool now. -- 11-01-05 Modified stock fuel tank internal fuel pickup to have I.D. of 3/8 inch, this eliminated cold start slow idle and bogg on acceleration. Now adding 1 ounce each of acetone and pure gum spirits of turpentine to each 5 gallons of any blend, seems to help keep the fats in solution to a lower temperature --Heated 2nd tank fuel system installed january 2010, now running on a heated blend of 90% veg/5% diesel/5% RUG (no acetone or turpentine, heat replaced these).

HC - AT what temperature do you do this process ? You indicate the "suspended" fats are settled. My filter plugging is caused by fat that is already melted when I do the filterng, from testing it only takes a couple of degrees of nightime cooling to cause this dissolved (melted) fat to turn back into solid tallow. I have cooled oil to force this to happen but at 40 deg f the oil is so thick the tallow stays suspended for days, filtering this cold oil is a pain as you have to constantly clean or change filters. Always looking for a better solution.

---------------------------------------------------------------------92 dodge cummins with over 260,000 miles. Running an unheated 50% diesel/50% WVO blend for about the last 75,000 miles when temps above 50 deg f, no modifications or heating except the addition of a throw-away in-line fuel filter (removed during cold weather). As of 8-01-05 I have been testing a 75% WVO/15% gasahol (90% RUG/10% ethanol)/10% diesel blend. Works fine down to about 65 f then starts rough. Runs ok once engine warms up. Back to a 50/50 diesel blend sence 9-15-05, just to cool now. -- 11-01-05 Modified stock fuel tank internal fuel pickup to have I.D. of 3/8 inch, this eliminated cold start slow idle and bogg on acceleration. Now adding 1 ounce each of acetone and pure gum spirits of turpentine to each 5 gallons of any blend, seems to help keep the fats in solution to a lower temperature --Heated 2nd tank fuel system installed january 2010, now running on a heated blend of 90% veg/5% diesel/5% RUG (no acetone or turpentine, heat replaced these).

This sounds very much like the idea I had for heating WVO using Exhaust heat.

Original idea- Wrap exhaust (or make a donut) that fits around exhaust. Use 12v pump to push oil thru the thing at a rate that accomidates the raise in temprature desired. Pump controled by a thermastat. Too hot of oil and shut off pump. Heated oil goes to smaller "drive" fuel tank (not directly to IP) Drive tank has overflow that pushes oil back to storage tank.. If drive tank temp drops too much then process starts over. PROBLEM. You need a variable rate pump to accomidate fluxuation in exhaust heat. (cooler right after start up / hotter at operating temp etc.) Can you vary pump rate by lowering voltage going to it? Will this ruin a pump though?

Now thats the drive tank idea. Apply this to your flash idea would make the drive tank a cooling/storage tank cause 300 degrees to hot for fuel use.

SNIP

JMJ,I would not like the idea of driving around with 5, 10 or 20 gallons of oil at 300°F ready to scald me in an accident.I doubt that your insurer would like it either.

JMJ,I would not like the idea of driving around with 5, 10 or 20 gallons of oil at 300°F ready to scald me in an accident.I doubt that your insurer would like it either.

Point well taken though we are only speaking of a small flash tank (one gallon or less) that is that hot. Tim Cook desecribed his idea of one as being 5" diameter and a foot tall.

Your point does dictate though it would need to be double walled tank and that as this hot oil is moved to the storage tank on the vehicle it needs to go thru a cooler/radiator to drop the temp back down to something safer.

Originally posted by Tim c cook:HC - AT what temperature do you do this process ? You indicate the "suspended" fats are settled. My filter plugging is caused by fat that is already melted when I do the filterng, from testing it only takes a couple of degrees of nightime cooling to cause this dissolved (melted) fat to turn back into solid tallow. I have cooled oil to force this to happen but at 40 deg f the oil is so thick the tallow stays suspended for days, filtering this cold oil is a pain as you have to constantly clean or change filters. Always looking for a better solution.

Hi Tim,-- I settle out the fats water crud etc, unheated, at W/S temp so must be around 10-15 degrees C at present time.

My current pre-process, is when oil is recieved, its poured into an IBC, (large caged Industrial plastic palletised 1000L tank) When its around 3/4 full, I add around 4 buckets of un demethed (room temp) glyc, then continue filling IBC untill full with waste oil. I give the whole lot a stur with a pole for a few mins, then leave to settle. (Ive noticed that the oil doesnt clear as quick in an IBC, probably due to the fact that its lidded, but the fats etc, settle just as quick. My guess is, that some of the meth left in the glyc dissolves in the oil and causes the clouding.)

About vehicle fuel heating--There's no real need to resort to exhaust heating--Coolant heat exchange methods and coolant heated filters are much more reliable, with no danger of overheating the oil--As you say, it doesnt take much in the way of temperature increase to melt the remaining tallows in your veggy as it is!

No real need either, (Unless you live in very cold terratory) to supply additional heating to the veggy tank. As long as the gauze strainer in the tank is clear, and not too fine a mesh,(not smaller than 1mm pitch) the fuel lines are of good diameter (around 8mm ID)you shouldnt have problems with fuel delivery. A small amount of heat to the filter and you're all set.

HCII- the on board flash dewater unit (12v exhaust or otherwise) though could be one that makes on board filtering much more possible. Particularly for long distance travelers (campers, visting grandma etc.)

Also final dewatering if you plan to go commercial is a MUST thus this is a reason to explore this area.

Hc -- Yep, that's the problem - cold climate. This year it was still getting down to around 50 deg f until about 2 weeks ago, winter sees lots of -"0" f temps. even diesel can use some extra heat at these temps..

Flash evap unit -- The basic reason I came up with this dewatering unit is that this year I am collecting a lot more oil from restaurants. In doing so the oil gets thrashed a lot during transport. For some unknown reason I always find a lot of water in the transport tank, at least a couple gallons of water for each hundred gallons of oil. In transport this water gets well stirred into the oil. If I am finding 2 gallon of free water there must also be a lot of water as small droplets. My transport tank outlet is on the bottom of the tank, the first couple gallons out is usualy free water, then about 10-12 gallon of creamy water/oil emulsion, then oil.

I also am finding that I can save a LOT of money for filters by water washing the oil during settling, adding at least 10 % extra clean water and stirring it into a nice smooth emulsion. Let this settle for a week at 90 deg f and I can filter several hundred gallon of oil to 5 micron before I have to replace the filters. Prior to the water washing/settling I was replacing my 4 (40-20-10-5 micron) filters after 75-150 gallon of oil, sometime even less.

Dana has convinced me that water is probably causing slow, long term, increased wear to the injection pump and free water is potentialy disasterous to the injection pump.

I have water in my oil, I am adding water to my oil for washing, Water causes wear, free water causes pump failure -- I think I should dewater my oil ..

dewatering while on the move -- There have been several prior discussions on this topic, none ever came up with a solution I thought practical. I think some type of flash evap unit could do the job but I see at least 2 limitations, 1 = output flow rate 2 = a lot of heat required, at least by automotive electrical standards.

From testing I find that for around 1000 watts of heat you can dewater around 2 gallon of oil/hour with no insulation and no heat recovery to preheat the incoming oil. If heat exchanger tubing is installed into the flash tank and the steam condensing tank to route the incoming oil through to preheat it, I think that at least 1/2 the heat can be recovered. this should allow the same 2 gallon/hour of oil to be dewatered using 500 watts of heat instead of 1000 watts (once the unit is up to temp). This also reduces the outgoing dry oil temp down from the 300 degrees to something around 200 or a bit more, have to build it to be sure just what this temp ends up being.

500 watts of heat using 12 volts DC requires 41.66 amps continuously, hour after hour. This requires a big alternator. It can be done, my dodge alternator is rated at 120 amps at speed. I suspect even running lights and air cond it could supply all the power required until I hit a town or some other reason to have to slow down, then even this alternator would not likely be able to supply everything.

The 500 watts heat, plus heat recovery, will likely be able to dewater 2 gallon/hour but with a load on my truck I burn around 4 gallon/hour (15 miles/gallon - 60 miles/hour) so this 500 watt unit is not able to supply oil anywhere near the rate being consumed, not by using just 12 volt for the heat. to increase the gallon/hour throughput you must have more heat, just a fact, no other way to do it. This is why I was looking at using exhaust heat. with a load on the truck my exhaust heat runs from around 300 degrees when coasting down-hill, to a bit over 1100 degrees on a long hard uphill. This much heat would allow the flow rate to increase several times over the 2 gallon/hour. The flow rate must be automatically controlled to insure the oil temp does not go above the oil's flash point ( a bit over 300 degree depending). The variable flow rate and the use of waste exhaust heat would allow some sort of flash evap unit to actualy meet the requierments of on-board mobile dewatering. The size is also small enough to be practical. It is not going to be practical on your volkswagon but would be doable in a box truck or a tour bus or a motor home or even a pickup truck towing a trailor.

This dewatering unit and a LOT of filtering (settling and water washing just not likely)would allow you to travel without needing to carry several hundred gallon of oil. This is MY goal.. ( It takes around 230 gallon of oil for me to make a round trip from Illinois to arizona). .

---------------------------------------------------------------------92 dodge cummins with over 260,000 miles. Running an unheated 50% diesel/50% WVO blend for about the last 75,000 miles when temps above 50 deg f, no modifications or heating except the addition of a throw-away in-line fuel filter (removed during cold weather). As of 8-01-05 I have been testing a 75% WVO/15% gasahol (90% RUG/10% ethanol)/10% diesel blend. Works fine down to about 65 f then starts rough. Runs ok once engine warms up. Back to a 50/50 diesel blend sence 9-15-05, just to cool now. -- 11-01-05 Modified stock fuel tank internal fuel pickup to have I.D. of 3/8 inch, this eliminated cold start slow idle and bogg on acceleration. Now adding 1 ounce each of acetone and pure gum spirits of turpentine to each 5 gallons of any blend, seems to help keep the fats in solution to a lower temperature --Heated 2nd tank fuel system installed january 2010, now running on a heated blend of 90% veg/5% diesel/5% RUG (no acetone or turpentine, heat replaced these).

Sorry, Tim, Now I can see your problem--The sheer quantity of oil that you are dealing with, and the sort of mileage you are doing I wasnt aware of!

Trust me to get the wrong end of the stick!

A flash evap unit, if it could be made portable enough to fit in your truck, would sort a lot of probelms for you, maybe with a combination of elec. heat and exhaust heating--How do you currently dry your wvo?Maybe a combination of glyc pre-treatment and settlement with spray-drying after would help out untill you got the flash evap online.

How about building a "hood". the oil and water vapor would condense back to liquid on the SS hood surface and run down the hood to a trough into a collection bin of some sort. That is how the hood works in my rest. Maybe a small one would work here?

HC -- Drying -- Up until recently I was not drying, hadn't seen any water in the oil going into my truck fuel tank and never had any water when draining the fuel filter so assumed all was well. -BUT- this winter the truck was starting just a bit slower than in the past, even on diesel, this set me to worrying about dana's explination of small water drops causing increased wear in the injection pump over time. Finaly decided dewatering was worth the peace-of-mind.

I tried the spray technique, ran it for 3 days, barely made any differance. It sure is messy, oil spray on everything within 10 feet of the barrel. It may work ok with biodiesel but It did not do much for straight oil, even with heat. This is why I began looking for another way.

For now I will just set the prototype up a bit different when dewatering more oil. I realy don't burn all that much fuel until I do a long haul delivering something or visiting friends (Arizona or Florida in the winter, Montana or Idaho in the summer) so I can dewater 20 gallon every couple weeks and get by.

pizzaman -- Sounds possible, I will be trying all sorts of ideas in the future. I will set the prototype up to test a different idea each time I need to dewater another 20 gallon of oil, may take a while but at least I will have a better idea of what does or does not work. First tests will be to screw a piece of pipe into the outlet of the ball valve and run the oil through some calibrated flow-rate oil burner nozzles. While doing this I will try several ways to contain the steam.

My neighbor just tossed out an electric cookstove, I salvaged the oven thermostat from it to use to control the heating element inside the pipe so I can also test how well this works. with the thermostat installed I will not need to manualy adjust the ball valve every few seconds, Especialy when using a calibrated oil burner nozzle to control the flow rate, the thermostat will control the amount of heat directly rather than adjusting the flow rate of the oil to control the heat. I hope - anyway.

I will also try an AC voltage controlling veriac in front of the 12 volt DC battery charger to control the voltage applied to the shurflo pump in an attempt to regulate the pressure more precicely. testing is fun.

---------------------------------------------------------------------92 dodge cummins with over 260,000 miles. Running an unheated 50% diesel/50% WVO blend for about the last 75,000 miles when temps above 50 deg f, no modifications or heating except the addition of a throw-away in-line fuel filter (removed during cold weather). As of 8-01-05 I have been testing a 75% WVO/15% gasahol (90% RUG/10% ethanol)/10% diesel blend. Works fine down to about 65 f then starts rough. Runs ok once engine warms up. Back to a 50/50 diesel blend sence 9-15-05, just to cool now. -- 11-01-05 Modified stock fuel tank internal fuel pickup to have I.D. of 3/8 inch, this eliminated cold start slow idle and bogg on acceleration. Now adding 1 ounce each of acetone and pure gum spirits of turpentine to each 5 gallons of any blend, seems to help keep the fats in solution to a lower temperature --Heated 2nd tank fuel system installed january 2010, now running on a heated blend of 90% veg/5% diesel/5% RUG (no acetone or turpentine, heat replaced these).

I will also try an AC voltage controlling veriac in front of the 12 volt DC battery charger to control the voltage applied to the shurflo pump in an attempt to regulate the pressure more precicely. testing is fun.

Tim, I use a 600W light dimmer to control the AC to my 24V 10A charger when charging 6v & 12V batteries. As the charger is not a regulated one, I still need to monitor the current and voltage on the battery to determine when to stop charging.

With vegoil which is suspected of being wet, get some biodiesel byproduct (glycerol) and mix in around 10% of byproduct into the vegoil. This should absorb the water and settle to the bottom of the vessel.The dry vegoil should be able to be decanted from the top of the glycerol. This seems to remove many solid contaminants as well.Be sure to check before and after this process, to see how well it works for you. I have been told that it also causes the high MP oils to be retained with the byproduct.

Tony -- Regarding the lamp dimmer -- I assume this is the normal hardware store dimmer designed for regular incandescent bulbs. If so, check the transformer in your battery charger for heat. These dimmers chop the normal 110 volts AC sine wave into extremely fast switching pulses using SCR's. The high freq switching causes a lot of extra heat in a transformer. I once had to do a redesign of around 50 existing dimmers as the SCR switching was causing the failure of several $250.00 transformers each year, always at the worst time, and with a lot of smoke and smell, always during a public planetarium show.

My experiance so far is that used oil IS ALWAYS wet, at least to some extent. Testing with the flash evaporator confirms this to me, always get at least a bit of steam. Doing the "frypan bubble test" I find bubbles in any of my oil that has not been through the dehydrator.

Glycerol drying/settling --I will give this a try once I get a 25 gallon processor built. I hope to run my process this winter using a biodiesel fired boiler and generator.

My hope is to seperate tallow from the good oil, turn the tallow into biodiesel for the boiler and generator as they will be located inside a heated shed.

Have any ideas of how to seperate tallow from oil or from the wet glycerin ?

The only concept I have come up with so far is to cool the oil so the tallow solidifies. The problem I find is that when the oil is cooled to 40 deg f the tallow solidifies ok but the oil is so thick the tallow can not settle.

In reading magyver's "different way to filter" thread (here) He describes floating drops of oil up through water. In doing this he gets 2 layers, good oil on top and sort of a "gravy" of tallow. I will build one of these "float" tanks (100 pound propane bottle) and try this, may need to control the temp of the water ? Too many projects to build all at once..

---------------------------------------------------------------------92 dodge cummins with over 260,000 miles. Running an unheated 50% diesel/50% WVO blend for about the last 75,000 miles when temps above 50 deg f, no modifications or heating except the addition of a throw-away in-line fuel filter (removed during cold weather). As of 8-01-05 I have been testing a 75% WVO/15% gasahol (90% RUG/10% ethanol)/10% diesel blend. Works fine down to about 65 f then starts rough. Runs ok once engine warms up. Back to a 50/50 diesel blend sence 9-15-05, just to cool now. -- 11-01-05 Modified stock fuel tank internal fuel pickup to have I.D. of 3/8 inch, this eliminated cold start slow idle and bogg on acceleration. Now adding 1 ounce each of acetone and pure gum spirits of turpentine to each 5 gallons of any blend, seems to help keep the fats in solution to a lower temperature --Heated 2nd tank fuel system installed january 2010, now running on a heated blend of 90% veg/5% diesel/5% RUG (no acetone or turpentine, heat replaced these).

I am not having much success finding oil burner nozzles that have a flow rate higher than 2 gal/hour. The nozzle manufacturers web sites list flow rates from less than 1/2 gal/hr up to around 100 gal/hour but they do not sell retail. I find retail sellers on the web but they only stock nozzles from around 2 gal/hr or less, some will special order other nozzles but at a higher price. Nozzle pricing seems to start around $10.00 each for the ones in stock, more for special orders.

I found this 11 page pdf file (here). It gives detailed info an how a burner nozzle is constructed and what it is supposed to do. Unfortunatly oil burner nozzles are designed to create very tiny droplets so that it takes only a small amount of additional heat to vaporize them so they will burn, this is NOT what I want to have happen in this evap unit. Another aggravation is that the oil burner nozzles all use a non-standard 5/8 - 24 thread, this requires the use of an adapter coupling. All the couplings that I find listed are made of brass, from experiance I know brass will grow a green crud, especialy at the 300 degree f temps inside the evap chamber.

All these reasons have me looking for some other orifice device. Looks like there is a much simpler and cheaper nozzle available for less than $5.00 each. -- LIQUID PROPANE GAS BURNER NOZZLES. Every restaurant supply retailer on the web as well as several ebay stores stock these in a huge selection of orifice sizes and in both male and female pipe threads. These nozzles are simply calibrated holes through a brass fitting (yes, brass -unfortunately). These should work just fine for the evaporator, the ball valve removed all the water from the oil and it is a much cruder orifice than these units. The only thing is that being gas nozzles they are not listed with a gallon/hour rating. The standard way of designating these is to use the diameter of the orifice but not as an actual measurment but by indicating the number of the wire guage drill that was used to make the hole (never easy).

It will be nescicary to guesstimate the gallons/hour by using info about oil burner nozzle sizes. This in a bit tough as the oil burner manufactuers do not tell you what size orifice is used with what gallon/hr rating.

I have only found 2 references that equate orifice diameter with gallons/hr --

(unfortunatly the orifice diameter/flow rate calculations for these don't match. If you increase the g/h flow of #1 until you get 10.4 it's orifice diameter is .o28 -BUT- reference #2 indicates a flow of 8.5 g/h with an orifice diameter of .050 ?? I am still Looking for more references, will most likely just have to buy a few of these and deturmine the flow rate by measuring it directly.)

Flow is based on the AREA of the orifice, if you double the DIAMETER of the orifice you increase the AREA (and the flow) 4 times.

If .007 flows .65 g/h -then- .014 will flow be 4 times larger, or 2.60 g/h. -- double the orifice diamiter again to .028 and the flow will be 10.4 g/h.

If you increase the diameter of the orifice by 1.5 times you will DOUBLE the flow.

using this info it is possible to guesstimate the flow for any given size orifice. There are a couple "rules of thumb" here that sort of cancel each other out. -- the oil burner gal/hour rating is based on 100 pounds pressure, I want to use 150 pounds pressure. The flow is doubled only if you apply 4 times the pressure. - SO- First rule of thumb - If you run an oil burner at 150 pounds you need to increase the gallon/hour rating by 20% to give you the rating at 150 pounds. -- unfortunatly there is another rule concerning the thickness of the metal plate that the orifice hole is placed in that says if the metal is thin the orifice will flow 1/4 to 1/3 more than if the same sized orifice hole is placed in a thick metal plate. -- The LP nozzles use a thick orifice plate but the oil burner nozzles use a thin orifice plate. -- -so- now we have to SUBTRACT 20%-30% of the flow we calculated for an oil burner nozzle with 150 pounds pressure to get the actual flow through a LP nozzle that has the same diameter orifice hole.. -SO- sence the different design of the LP nozzle closely cancels out the added flow in the oil burner nozzle caused by the additional 50 pounds pressure we can just use the basic flow rate of an oil burner nozzle that is calibrated for the normal 100 pounds pressure (I hope).

To pick the correct LP nozzle -- First pick the gallons/hour you want to flow - calculate the diameter of the orifice hole that is needed for that flow rate by starting with one or the other of the 2 known flow rate/orifice size examples given above. We now need to translate the orifice diameter into a wire guage drill number. There are web pages that give this list, one is here. This gets us to a rough guesstimate of what LP gas nozzle to start with that will be someplace close (I hope) to the desired gallons per hour flow rate.

---------------------------------------------------------------------92 dodge cummins with over 260,000 miles. Running an unheated 50% diesel/50% WVO blend for about the last 75,000 miles when temps above 50 deg f, no modifications or heating except the addition of a throw-away in-line fuel filter (removed during cold weather). As of 8-01-05 I have been testing a 75% WVO/15% gasahol (90% RUG/10% ethanol)/10% diesel blend. Works fine down to about 65 f then starts rough. Runs ok once engine warms up. Back to a 50/50 diesel blend sence 9-15-05, just to cool now. -- 11-01-05 Modified stock fuel tank internal fuel pickup to have I.D. of 3/8 inch, this eliminated cold start slow idle and bogg on acceleration. Now adding 1 ounce each of acetone and pure gum spirits of turpentine to each 5 gallons of any blend, seems to help keep the fats in solution to a lower temperature --Heated 2nd tank fuel system installed january 2010, now running on a heated blend of 90% veg/5% diesel/5% RUG (no acetone or turpentine, heat replaced these).